Isolated chorda tympani injury following petrous temporal fracture

Improved visualization of the chorda tympani nerve using ultra-high-resolution computed tomography

Background

Recognition of the anatomical course of the chorda tympani nerve (CTN) is important for preventing iatrogenic injuries during middle-ear surgery.

Purpose

This study aims to compare visualization of the CTN using two computed tomography (CT) methods: conventional high-resolution CT (C-HRCT) and ultra‐high-resolution CT (U-HRCT).

Materials and methods

We performed a retrospective visual assessment of 59 CTNs in normal temporal bones of 54 consecutive patients who underwent both C-HRCT and U-HRCT. After dividing CTN into three anatomical segments (posterior canaliculus, tympanic segment, and anterior canaliculus), two neuroradiologists scored the visualizations on a four-point scale.

Results

On C-HRCT, the visual scores of the posterior canaliculus, tympanic segment, and anterior canaliculus were 3.5 ± 0.7, 1.6 ± 0.6, and 3.1 ± 0.7, respectively. The respective values were significantly higher in all segments on U-HRCT: 3.9 ± 0.2, 2.4 ± 0.6, 3.5 ± 0.6 (p < 0.01). Although the difference in scores between methods was greatest for the tympanic segment, the visual score on U-HRCT was lower for the tympanic segment than for the anterior and posterior segments (p < 0.01).

Conclusion

Ultra‐high-resolution CT provides superior visualization of the CTN, especially the tympanic segment.

Patterns of intracranial hemorrhage in petrous temporal bone fracture

OBJECTIVE

To study the relationship pattern of intracranial hemorrhage in cases of traumatic petrous temporal bone fracture.

METHODS

All head injury cases admitted to the Emergency Department, Hospital Tengku Ampuan Afzan, Pahang, Malaysia in 2008 were assessed. Computerized tomography (CT) scan of the skull base was performed in indicated cases. Patients with a petrous temporal bone fracture were included in the study. Subsequent magnetic resonance imaging (MRI) was performed. Intracranial hemorrhages incidence, management and outcome were recorded.

RESULTS

From 1421 cases of head injury, 49(3.4%) patients were diagnosed to have a petrous bone fracture from the CT scan. Only 46 cases underwent MRI scan and were included in this study. Of these, 36(78.3%) cases had associated intracranial hemorrhages (p<0.01). Intracranial hemorrhage was associated with the longitudinal types of petrous fracture (p<0.05). Subdural hematoma was the most prevalent type of bleed (55.6%). There was no association between the types of intracranial bleeding (extradural, subdural, subarachnoid or intracerebral hemorrhage) and the types of petrous bone fracture (longitudinal, oblique or transverse). The mortality rate was 17.4%. The mortality cases were associated with the presence of other skull bone fractures (p<0.05).

CONCLUSIONS

Petrous fracture is significantly associated with intracranial hemorrhage. There was no association between the types of petrous fracture and the types of intracranial hemorrhages in our material.